Method of conveying material



1954 R. M. CARRIER, JR.. ET AL 2,690,835

METHOD OF CONVEYING MATERIAL Original Filed Feb. 28, 1948 3 Sheets-Sheetl E I I 1.-

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METHOD OF CONVEYING MATERIAL Original Filed Feb. 28, 19-48 3Sheets-Sheet 2 [EVEN/GT5 ROBERT M CARR/[R J72 MAUR/CE G. Wwnn R; M.CARRIER, JR., ETAL 2,690,835

METHOD OF CONVEYING MATERIAL Original Filed Feb. 28, 1948 Oct. 5, 1954 3Sheets-Sheet 3 [Eran/0P ROBERT M CARR/ER IR MAURICE G W Patented ct. 5,1954 STATES ?ATENT OFFICE METHOD OF CONVEYING MATERIAL Originalapplication February 28, 1948, Serial No.

11,998. Divided and this application September 23, 1950, Serial No.186,342

1 Claim.

This invention relates generally to materials handling and moreparticularly to a method of conveying a material in accordance with thedirectional throw principle.

The subject matter of this disclosure constitutes a division of ourco-pending application U. S. Serial No. 11,998, filed February 28, 1948,now Patent No. 2,630,210.

It has been observed that the inherent elasticity of a spring memberendows the spring member with certain physical characteristics, forexample, work must be performed in defleeting a spring, however, oncedeflected, the spring will exhibit a vibration characteristic somewhatsimilar to the periodic action of a pendulum.

In other words, a spring may comprise one component of a vibratingsystem having a degree of freedom whereby the spring will vibrate in apredetermined direction.

If a vibrating system partakes of free harmonic vibrations, resistingforces are always present which will cause a gradual damping of theoriginal vibrations either through air or fluid resistance or internalfriction of the vibrating body or other interfering forces. It ispossible, however, to apply a periodical disturbing force to a vibratingsystem to produce a forced vibration and in so doing, a magnificationfactor may be exploited.

We have found that when the frequency of the periodic disturbing forceapproaches the frequency of natural vibrations of a vibrating system andthe damping forces are small, the magnification factor becomes unusuallylarge. The result of this phenomenon is that a small periodicaldisturbing force may produce a very large forced vibration provided thatthe periodical disturbing force is in resonance with the naturalvibrations of the system and is maintained in resonance.

One of the types of conveyors that has come into use within recent yearsis the so-called feeder conveyor which operates on a directional throwprinciple. A reciprocating or oscillating plate is moved forwardly andupwardly carrying the material placed thereon along with it, however,the direction of movement thereof is changed rather abruptly and theplate is withdrawn from under the material, allowing it to fall in a newrelative position on the plate. The relative movement between thematerial and the plate not only assists in conveying the material, butthe initial movement of the plate is usually of such a character as topartially throw the 2 material in the direction of travel, hence, theidentification of such equipment as a directional throw conveyor.

In accordance with the principles of the present invention, we provide afeeder type conveyor operable on the directional throw principle and,availing ourselves of the characteristics of a vibrating systempartaking of forced harmonic vibrations, operate the conveyor accordingto a novel method which permits the use of more economical machinery toconvey material with greatly increased efficiency.

Briefly, the method of directionally throwing a conveyable materialpracticed in accordance with the disclosure of the present inventioncontemplates the supporting of the conveyable material resiliently onspring means having a predetermined selected spring constant. An energyimpulse generating means is then operated in resonance with the naturalvibrations of the spring means, which, in effect, form a vibratingsystem. In addition, the energy impulse generating means are positivelycoupled to the spring means and the entire train of mechanism isvibrated simultaneously at a common fixed and predetermined frequency.

The practice of the method thus provided permits the full exploitationof a, high magnification factor due to the advantageous use of thedynamical conditions in the vibrating system so that a very small motormay be employed and the entire conveying apparatus may be economicallyproduced from a simplified structure.

It is an object of the present invention, therefore, to provide a,method of directionally throwing a conveyable material which exploitsthe characteristics of a forced vibration vibrating system.

Another object of the present invention is to provide a method ofconveying a material with a vibrating system whereby a largemagnification factor may be exploited.

Yet another object of the present invention is to provide a method forconveying a material wherein the material is vibrated in resonance withthe natural vibrations of the conveying system apparatus.

Still another object of this invention is to pro vide a method ofcausing material to be conveyed up a spiral or in the direction of atrough using the principle of natural frequency in a directional throwtype conveyor.

Many other features, advantages, and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description which follows and the accompanyingsheets of drawings in which several preferred forms of structure areshown which are capable of practicing the steps of the method of ourinvention.

On the drawings:

Figure 1 is a fragmentary front elevational view of a spiral conveyoroperable in accordance with the principles of the present invention.

Figure 2 is a fragmentary side elevational view partly in section, ofthe spiral conveyor of Figure 1.

Figure 3 is a fragmentary elevational view of one type of springmounting which may be provided for the conveyor of Figure 1.

Figure 4 is a fragmentary vertical sectional view taken substantially online IV-IV of Figure 3.

Figure 5 is a fragmentary elevational view of a modified drive means forthe conveyor of Figure 1.

Figure 6 is a side elevational view of a trough type conveyor providedin accordance with the principles of the present invention;

Figure 7 is a horizontal sectional view taken substantially on lineVIIVII of Figure 2.

Figure 8 is a fragmentary vertical sectional view taken on line VIIIVIIIof Figure 2.

As shown on the drawings:

The embodiment of Figures 1 and 2 includes a frame support structure Ein which a helical conveying flight II is supported for oscillationabout a substantially vertical shaft l2 and for reciprocation in avertical direction relative to the frame structure.

The conveyor is arranged to move material up the flight through atwisting, upward movement at a fixed angle to the angle of climb of theflight. The movement of the flight is then abruptly terminated andreversed whereupon the flight is twisted downwardly so that the materialsupported on the flight will be partially impelled in the initialgeneral direction of the flight and will also fall on an angularlyadvanced portion of the flight relative to its starting position.

The frame structure l0 includes a base l supported in spaced relation tothe floor by foot members I6 disposed at each corner. A pair of verticalangle members I! and !8 are secured at each side of the base in spacedrelationship to one another and carry between them a pair of curvedguide plates -28 each having a slanted guide slot 2|.

A top plate 22 including a platform portion 23 extends outwardly fromthe frame structure at the upper ends of the angle members I! and I8 andis additionally braced by angle members 24 and diagonal brace 25,thereby providing a firm support for a motor '26 provided to drive theconveyor through a belt 21.

A second platform member 28 is spaced downwardly from the top of theplate 22 and carries a bearing member 29 in which the shaft I2 isjournaled.

The conveying flight comprises a series of separate units 30 securedtogether on the shaft :2 by means of a nut 32 received on an upperthreaded portion 33 of the shaft l2, each of the units 33 including aportion of an upwardl winding trough 34 integrally formed on a length oftubing 35 equal in length to the pitch of the flight.

The nut 32 bears downwardly on a circular closure plate 36 which isseated on a recessed ledge 38 on the upper end of the uppermost tube 35.It will be noted that the lower end of each section of tubing has adownwardly projecting rim 39 which is adapted to seat on the recessedledge at the upper end of the section of tubing therebelow.

The shaft l2 has an enlarged lower end Q3 providing a shoulder 44against which a bottom closure plate 4| abuts when the nut 32 is drawnup on the shaft l2, thereby placing the several flight units in firmassembly for co-rotation with the shaft [2.

A loading chute 45 is secured to the bottom unit of the conveyor and adischarge chute it is also secured to the top unit of the conveyor.

In accordance with the principles of the present invention, the shaft I2is journaled in a bearing 4? but is resiliently mounted on a coil spring48, thereby establishing a vibration sys tem. An anti-friction bearingassembly 49 freely disposed about the shaft l2 between the spring 48 andthe bottom closure plate ll so that the shaft l2 will be free tooscillate.

It will be understood that the coil spring 48 will have a predeterminedspring constant which will determine the natural vibrating frequency ofthe vibrating system, however, the natural vibrating frequency of theentire system be selectively varied by securing one or more coil springsbetween the platform 49 and base plate I5.

In order to impart a reciprocating movement to the helical conveyingflight H, a drive shaft 5! journaled in a pair of bearing blocks 52mounted on the top plate 22 is rotated through a pulley drive from themotor 25. An eccentric E3 is carried by the drive shaft 55 and engages aconnecting rod 54 operatively connected to the upper end of the conveyorshaft l2 through a ball joint 55. A train of mechanism is thus providedto impart a periodical disturbing force to the vibration system.

In order to oscillate the conveyor flight H, a pair of rollers 58 areeach rotatably secured on a corresponding axle 59, each axle beingrigidly fixed to opposite sides of the trough 312 and arranged so therollers 58 will engage one of the slanted guide slots 2i formed in eachof the curved plates 26 (Figure 8). Thus, as the conveyor flight isreciprocated vertically, the rollers 58 moving through the guide slots2! will cam the flight along an oscillatory path relative to the centeraxis of the flight, the angularity of the slots determining the degreeof oscillation.

In Figure 5, a modified driving mechanism is shown which includes a leafspring EEG welded at I08 to one of the frame members I? and carrying abearing use through which a shaft H2 passes freely. A pair of collars iii are keyed to the shaft H2 above and below the bearing Hi9 whereby theshaft is free to rotate but must vibrate vertically with the bearing Hi9and the leaf spring fill.

A cylinder HE! is mounted on a shaft [2 to which the flight conveyor 88is assembled and a piston H3 is secured to the lower end of the shaft H2and is adapted to be reciprocated in the cylinder IID. A seal H4 isprovided to preelude leakage of fluid outwardly from the cylinder alongthe shaft H2. The cylinder HE! is filled with a fluid such as oil and arestricted orifice H5 is provided in the piston H3 to afford restrictedflow communication between opposite sides of the piston I I3.

It will be understood that the restricted orifice H5 will permit thepassage of the fluid from one side of the piston to the other under the.AAA

5 effect of a slow displacement produced, for example, by the yieldingmovement of the conveyor flight 68 under the influence of increasedload, however, rapid relative movement as when a periodic disturbingforce is applied will result in movement of the piston H3 in such amanner as to cause the cylinder H to be moved in synchronisin therewith.Thus, the shaft II2 together with the piston H3 and the cylinder IIOtogether with the shaft I2 will function as a relatively rigid link whenthe relative speed of movement between the shaft H2 and the shaft I2exceeds a predetermined minimum governed by the selection of the size ofthe orifice II5.

Referring now to Figures 3 and 4, an additional driving means is shownas including a lower platform I I6 having a sleeve II8 mounted thereonclosed at its upper end by an end member I I7 centrally apertured toreceive the end of the shaft I2. A nut H9 may be adjusted on the shaftI2 through an opening I20 formed in the sleeve MB.

A lever I23 pivoted in a fulcrum I24 is moved up and down by aneccentric mechanism driven from a drive means I25 similar to the motor26 of Figure l. The lever I23 is pivotally connee-ted to a push rod I26extending through the platform H6 and upwardly inside the sleeve II8 forconnection at its upper end to a piston I2! slidably mounted in acylinder I28. The cylinder i26 is supported by a rod I30 which in turnis connected to the sleeve II8 through a ball joint is! connected to adisk I32 welded across the inside of the sleeve H8. A restricted orificeI33 is formed in the piston I21 to establish restricted fiowcommunication through the piston. Thus,

the fluid cylinder I26 will act in the same manner as the cylinder IIOof Figure 6 to permit the conveyor to float on the spring mounting.

A plurality of cantilever type spring arms I34 are each adjustably heldin a corresponding plurality of blocks I35 by means of a set screw I36and each block I35 is secured by bolts I30 and I39 to a suitable baseI46. Near its upper end, each spring arm I34 passes through a segmentalcircular cut-out portion I44 formed in the platform H5. A block I45 isadjustably secured to each spring arm I34 by set screws I46 and eachblock M has a slanted brace I41 pivotally secured by a cap screw I48 tothe platform H6. It will be understood that the adjustment means permitsselective variation of the natural vibrating frequency of the vibratingsystem.

in Figure 6, the principles of the present invention are practiced witha trough-type conveyor which includes a trough I50 mounted substantiallyhorizontally on a plurality of cantilever type spring rods I5l, each ofthe spring rods i5I being adjustably secured in a plurality of blocksI52 and I53 arranged on both sides of the trough I50.

A motor I54 is provided having a power takeoff shaft to which isattached an eccentric I55 operatively connected to a connecting rod I55ahaving a piston I56 slidably mounted in a fluid cylinder I5? firmlyassembled on the end of a shaft E53 having a ball joint I58a on the endthereof connected to the conveyor trough I50. A restricted orifice I59is formed in the piston I56 so that the connecting rod I55a togetherwith the piston I56 and the cylinder I51 together with the shaft I56will operate as a relatively rigid link when a rapid relative movementoccurs therebetween. However, under the influence of a relatively slowdisplacement, the restricted orifice provides restricted communicationbetween opposite ends of the cylinder to permit adjustments in length ofthe linkage so that the conveyor trough I50 may settle on the cantilevertype spring I5! under the influence of additional conveying load.

Vie have observed that when a periodic disturbing force of low frequencyis applied to a vibrating system having a comparatively high naturalvibration frequency, the magnification factor decreases, however, as thefrequency of the periodic disturbing force approaches the frequency ofnatural vibrations of the system, the magnification factor becomeslarge. Insofar as practicing methods of conveying material with avibrating system is concerned, this means that a very small periodicaldisturbing force may be employed to produce a proportionately largeforced vibration provided that the periodical disturbing force is inresonance or very nearly approaches resonance with the natural vibrationfrequency of the vibrating system and is maintained in resonance withthe natural vibration frequency of such system.

One of the important steps of the method herein disclosed and to bepracticed with the various types of structural embodiments described indetail above, therefore, includes the step whereby the energy impulsegenerating means employed to provide a periodical disturbing force andthe vibrating system, the characteristics of which are determined by thespring support, are operated simultaneously through a relatively rigidphysical coupling so as to vibrate at a common fixed and predeterminedfrequency. Thus, by operating the impulse generating means or motor at afixed predetermined speed the periodical disturbing force Will alwaysremain in resonance with the natural vibration frequency of the systemand the forced vibration technique may be successfully employed to fullyexploit a magnification factor of high quantitative value which resultswhen the frequency of the disturbing force approaches the frequency ofnatural vibrations of the system.

In operation, therefore, the structures described in detail herein areemployed to support a conveyable material resiliently on a vibratingsystem, the frequency characteristics of which being establishedprimarily through spring means having a predetermined spring constant.An energy impulse generating means is operated at a predetermined fixedimpulse frequency which bears a predetermined proportional relationshipto the natural vibration frequency of the vibrating system in order toprovide a periodical dis-- turbing force. The periodic disturbing forceis applied to the vibrating system whereupon energy impulses areimparted to the supported material to throw the material directionally.The energy impulse generating means and the spring meansare physicallycoupled and locked together for synchronous operation so that theperiodical disturbing force provided by the energy impulse generatingmeans may at all times approach very nearly the frequency of the naturalvibrations of the vibrating system or, in other words, may substantiallyequal the natural frequency of the vibrating system. Thus, the energyimpulse generating means and the spring means or vibrating system areoperated simultaneously at a common fixed and predetermined frequencywith the result that we advantageously exploit a high magnificationfactor and are able to convey more material quickly with an improvedeconomical apparatus which requires comparatively small driving means.

We intend to embody within the scope of this invention, of course, allsuch modifications as reasonably and properly come within the scope ofour contribution to the art.

We claim as our invention:

The method of conveying which comprises supplying conveyable material toa resiliently mounted material support structure having a predeterminedundisturbed natural frequency of vibration along a predetermined pathoblique t0- the material supporting surface of the structure therebycausing the structure to settle on its resilient mounting to a levelaccording to the load of the material on the structure, and imposing apositive disturbing force to the structure which is substantially insynchronism with such natural frequency, and which is of substantiallyuniform amplitude equidistant above and below the level to which thestructure has settled under the load of material thereon.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,280,056 Broekhuysen Apr. 21, 1942 2,334,368 Wolf Nov. 16,1943

